1. Field of the Invention
The present invention relates to a danger avoidance system capable of avoiding the collision of a vehicle against obstacles and of reducing the effect of collision on a vehicle.
2. Description of the Prior Art
FIG. 1 is a block diagram of a danger avoidance system for a vehicle disclosed in Japanese Patent Laid-open (Kokai) No. 63-222939. Referring to FIG. 1, an ambient condition monitoring system 20 for monitoring the ambient conditions comprises a traveling lane detector 21 for detecting a lane in which the vehicle is traveling, an obstacle detector 22 for detecting obstacles in the sight of a driver, another obstacle detector 23 for detecting obstacles out of the sight of the driver, a signal light detector 24 for sensing signal lights, and a road surface condition detector 25 for detecting the surface conditions of the road. A driver monitoring system 40 for monitoring the mental and physical condition of the driver including his behavior comprises a line-of-sight detector 41 for detecting the driver's line of sight, a blink detector 42 for detecting the blinking of the driver, a blood pressure sensor 43 for measuring the driver's blood pressure, a pulse sensor 44 for determining the driver's pulse count, and a temperature sensor 45 for measuring the driver's body temperature. A safety condition determining unit 100 determines conditions for safe traveling on the basis of the output signals of the ambient condition monitoring system 20 and the driver monitoring system 40.
A vehicle condition monitoring system 10 for monitoring the behavior of the vehicle comprises a traveling speed sensor 11 for sensing the traveling speed of the vehicle, an acceleration sensor 12 for sensing the acceleration of the vehicle, an angular velocity sensor 13 for sensing the angular velocity of the vehicle, an accelerator pedal sensor 14 for sensing the position of the accelerator pedal, and a brake pedal sensor 15 for sensing the position of the brake pedal. A data comparison unit 110 determines the traveling behavior of the vehicle on the basis of the vehicle condition monitoring system 10 and compares the data representing the traveling behavior of the vehicle with safety conditions determined by the safety condition determining unit 100. A danger avoidance effecting system 60 for notifying the driver of danger and effects operations for avoiding danger or reducing the damage that will result from the danger comprises an audio device 61 which generates an audio warning, a warning display 62, the brake pedal 63 of the vehicle, the steering wheel 64 of the vehicle, and the accelerator pedal 65 of the vehicle.
The operation of the danger avoidance system will be described hereinafter with reference to a flow chart shown in FIG. 2. Suppose that the red signal light of a traffic signal installed at a crossing situated ahead is on and the driver has not recognized the red signal light through inattention. The signal light detector 24 of the ambient condition monitoring system 20 senses the red signal light on the traffic signal at the crossing situated 100 m ahead and the ambient condition monitoring system 20 provides a red light signal indicating that the red signal light is on. The line-of-sight detector 41 of the driver monitoring system 40 detects the driver's line of sight and the driver monitoring systems provides an inattention signal indicating that the driver's eyes are off the traffic signal. In step ST11, the red light signal and the inattention signal are transmitted through an input interface to the safety condition determining unit 100. In step ST12, the safety condition determining unit 100 determines safety conditions "Watch ahead and decelerate" for safety traveling on the basis of the red light signal and the inattention signal.
Meanwhile, the vehicle condition monitoring system 10 provides a traveling speed signal representing a traveling speed of 50 km/hr, an acceleration signal representing an acceleration of 0, and an angular velocity signal representing an angular velocity of 0 detected respectively by the traveling speed sensor 11, the acceleration pedal sensor 12 and the angular velocity sensor 13. In step ST13, these output signals of the vehicle condition monitoring system 10 are given through the input interface to the data comparison unit 110. Then, in step ST14, the data comparison unit 110 determines the traveling condition "Straight traveling at 50 km/hr" of the vehicle on the basis of the vehicle condition monitoring system 10. In step ST15, the data comparison unit 110 compares the safety conditions "Watch ahead and decelerate" determined in step ST12 and the traveling conditions "Straight traveling at 50 km/hr" determined in step ST14.
In this case, since the traveling mode of the vehicle does not meet safety traveling conditions, the data comparison unit 110 decides that the traveling mode of the vehicle is dangerous and gives instructions for danger avoidance to the danger avoidance effecting system 60. Then, the danger avoidance effecting system 60 drives the audio device 61 and the warning display 62 in step ST16 to urge the driver to take measures for avoiding danger by giving an audio warning "The red signal light is on. Decelerate immediately." by the audio device 61 and visually displaying a warning to that effect on the warning display 62.
Suppose that the red signal light of a traffic signal installed at a crossing situated ahead is on, the driver has recognized the red signal light, and the driver's foot is about to shift from the accelerator pedal to the brake pedal to stop the vehicle. The ambient condition monitoring system 20 provides a red light signal indicating that the red signal light of the traffic signal at a crossing situated 100 m ahead, and the driver monitoring system 40 provides a normal state signal indicating that the driver is neither looking aside nor dozing. The red light signal and the normal state signal are transmitted through the input interface to the safety condition determining unit 100 in step ST11. In step ST12, the safety condition determining unit 100 determines a safety condition "Decelerate" on the basis of the red light signal provided by the ambient condition monitoring system 20 and indicating that the red signal light of the traffic signal at the crossing situated 100 m ahead is on, and the normal state signal provided by the driver monitoring system 40 and indicating that the driver is neither looking aside nor dozing.
Meanwhile, the vehicle condition monitoring system 10 provides a traveling speed signal representing a traveling speed of 50 km/hr, an acceleration signal representing an acceleration of 0, and an angular velocity signal representing an angular velocity of 0. Then, in step ST13, the data comparison unit 110 receives these output signals of the vehicle monitoring system 10 through the input interface. In step ST14, the data comparison unit 110 determines a traveling condition "Straight traveling at 50 km/hr" of the vehicle on the basis of the output signals of the vehicle monitoring system 10. In step ST15, the data comparison unit 110 compares the safety condition "Decelerate" determined in step ST12 and the traveling mode "Straight traveling at 50 km/hr" of the vehicle detected in step ST14, decides that the traveling mode of the vehicle is dangerous, and gives instructions for danger avoidance to the danger avoidance effecting system 60. Then, in step ST16, the danger avoidance effecting system 60 drives the audio device 61 and the warning display 62 according to the instructions given thereto by the data comparison unit 110 to give an audio warning "The red signal light is on. Stop the vehicle immediately." by the audio device 61 and to display to that effect on the warning display 62 so that the safety traveling conditions are secured.
Suppose that the driver is looking aside while the vehicle is traveling on a clear, straight road. The ambient condition monitoring system 20 provides signals indicating that the road running ahead is straight and clear, and the driver monitoring system 40 provides a signal indicating that the driver is looking aside. In step ST11, the safety condition determining unit 100 receives these output signals of the ambient condition monitoring system 20 and the driver monitoring system 40 through the input interface. In step ST12, the safety condition determining unit 100 decides a safety condition "Watch ahead" on the basis of the output signal of the ambient condition monitoring system 20 indicating that the road is straight and clear, and the output signal of the driver monitoring system 40 indicating that the driver is looking aside, because, although there is no risk of collision, taking the driver's eyes off the road is dangerous.
The vehicle condition monitoring system 10 provides signals representing the traveling speed, the acceleration and the angular velocity of the vehicle. In step ST13, the data comparison unit 110 receives these output signals of the vehicle condition monitoring system 10 through the input interface. In step ST14, the data comparison unit 110 determines the traveling mode of the vehicle on the basis of the output signals of the vehicle condition monitoring system 10. In step ST15, the data comparison unit 110 compares the safety condition "Watch ahead" determined in step ST12 and the traveling mode of the vehicle determined in step ST14, decides that the traveling mode is dangerous, and give instructions for danger avoidance to the danger avoidance effecting system 60. Then, in step ST16, the danger avoidance effecting system 60 drives the audio device 61 and the warning display 62 according to the instruction given thereto by the data comparison unit 110 to give an audio warning "Watch ahead." and to display a visual warning to that effect on the warning display 62 so that the safety conditions are secured.
However, the known danger avoidance system thus constructed gives a warning even if the driver has recognized dangerous conditions and the driver is taking measures to avoid a traffic accident, or even if the driver looks aside intentionally when there is not any danger. Such a mode of operation of the danger avoidance system is annoying.